All fractures united without cast revision. Mean cast time was 4.5 weeks (range, 16 days–6 weeks). Immediate postoperative alignment was 2.5° varus (range, 11° valgus to 16° varus) and 7° procurvatum (range, 1° recurvatum to 22° procurvatum). Mean shortening was 1.5 cm (range, 0-2.7 cm). Final alignment was 1° valgus (range, 9° valgus to 12° varus) and 5° procurvatum (range, 0° to 22°). Mean follow-up was 8 months. There were no cases of skin maceration or cast failure. No casts precluded use of a spica car-seat. Figure 4 shows a typical case with a midshaft fracture treated with closed reduction and casting for 4 weeks with good remodeling at final follow-up, 19 months after injury.
Discussion
Although single-leg walking spica casts have been shown to safely treat low-energy femur fractures in children 1 to 6 years old,7 length-unstable femur fractures, bilateral femur fractures, and patients with hip dysplasia continue to be managed with a double-leg hip spica construct. Cast integrity remains fundamental to the control of most fractures and prevention of cast-related complications, such as skin maceration and ulceration. Surgeons typically use spica cast reinforcement schemes—such as cast augments of the torso–limb junction, with multiple layers of casting material or incorporation of a connecting bar between the legs, typically constructed by overwrapping a wooden dowel in casting material—to improve the mechanical stability of casts.6 The present technique of creating a connecting bar from fiberglass casting material significantly simplifies the standard wooden dowel approach and provided excellent results in our treatment group in terms of cast integrity and fracture alignment. In addition, at our institution, a roll of fiberglass costs $2.10, whereas a wooden dowel costs $3 to $10 and can be difficult to locate if not frequently used. Other tube-shaped materials, such as the disposable material used to package implants and tubes, carry an even lower cost. However, we have found that a single fiberglass roll is most readily available and easiest to apply.
Although proper spica cast application remains important in managing pediatric trauma, it lacks a good technical description in the literature. In this technical report, we have presented our standard spica cast application method, which minimizes the range of cast complications that have been reported, from minor skin irritation to superior mesenteric artery syndrome. Two salient technical highlights are use of waterproof pantaloon liners and cast petaling, which we have found almost eliminate the morbidity of potential skin complications, reported to occur at a rate of 28%.8 In addition, we forgo applying the cast on the injured leg in segments. Application of a short-leg cast on the injured leg to allow traction on the leg during cast application is of dubious utility and may be potentially harmful, with described complications of peroneal nerve palsy and compartment syndrome.9-11 Further, it is important to use an abdominal spacer (eg, a stack of towels) under the cast padding to create room for abdominal expansion and minimize pressure thought to induce superior mesenteric artery syndrome. Plastic or rubber abdominal spacers have also been described.12,13 Last, leg position is important for reduction and maintenance of the fracture, as well as patient care. Literature advocates minimizing hip abduction to just that needed for perineal care and maximizing hip flexion and knee extension to optimize car-seat fit and safety.14
Conclusion
Construction of a spica cast lower limb connecting bar from readily available fiberglass casting material allows a facile and rapid addition to the mechanical stability of a spica cast in the treatment of pediatric femur fractures. The technique is low-cost and obviates the need for additional extraneous materials.